A flush toilet bowl is disclosed in which flush water is spouted from a spout provided in the rim portion of the flush toilet bowl to generate a swirling flow for flushing the bowl (e.g., Patent Documents 1 and 2). In this type of flushing technique, adherence and persistence of soil and the like are less likely to occur on the inside of the rim of the toilet bowl, achieving good cleanability, and the entire surface of the bowl of the toilet bowl can be efficiently flushed with a small quantity of water.    Patent Document 1: JP-A-2001-271407 (Kokai)    Patent Document 2: Japanese Patent No. 3381261